I purchased two of the V2.0 boards from the store, never dreaming that they wouldn't have provision to adapt to the latest schematic.

I understand that P3 isn't on the board, that's not an issue. The issue is being able to stuff the board from the most recent schematic on which the part numbers are different from the original, and the circuit has changes as well.

The store shows the original schematic, but does nothing to help this situation.

I want to build the most recent schematic but could sure use some help with an updated stuffing guide, otherwise I guess I should return the V2.0 boards and look for a more recent design?

Sure would appreciate some help with this; every other purchaser must face the same dilema!

Jeff

I bought the boards too, but haven't had a chance to figure which traces to start cutting. I wish I didn't have to hack up the boards.

I think the F5 circuit in the F5 Turbo manual is the most recent version. So the resistors on the input are different values and have to be reconfigured, The thermistors need to be moved from the rails to the points between R7-Q3 and R8-Q4. And P3 added.

I purchased two of the V2.0 boards from the store, never dreaming that they wouldn't have provision to adapt to the latest schematic.

I understand that P3 isn't on the board, that's not an issue. The issue is being able to stuff the board from the most recent schematic on which the part numbers are different from the original, and the circuit has changes as well.

The store shows the original schematic, but does nothing to help this situation.

I want to build the most recent schematic but could sure use some help with an updated stuffing guide, otherwise I guess I should return the V2.0 boards and look for a more recent design?

Sure would appreciate some help with this; every other purchaser must face the same dilema!

Jeff

Hi,

The BOMs that correspond to that board has already the updated parts values. As you have noticed, the most recent iteration of the circuit has different part numbering, but the latest values have already been changed in the BOM. SO if you follow the BOM, you are actually building the latest version.

I bought the boards too, but haven't had a chance to figure which traces to start cutting. I wish I didn't have to hack up the boards.

I think the F5 circuit in the F5 Turbo manual is the most recent version. So the resistors on the input are different values and have to be reconfigured, The thermistors need to be moved from the rails to the points between R7-Q3 and R8-Q4. And P3 added.

The new values are already published in our BOM which is linked to from the product page. The location of the thermistors (one of it's leads) being on the transistor side rather than the rail side has of little to no difference at all in it's performance.

P3 can be added "off-board", but I was under the impression that one needs a distortion analyzer to perfectly adjust this. It wouldn't make any sense adjusting this by ear and everyone has this tool so maybe it makes more sense to leave P3 at the moment.

Cheers

Last edited by Jason; 21st December 2012 at 01:36 AM.
Reason: Added bold for emphasis and a link for convenience

As I've said, the new values are already locked in the BOM. The location of the thermistors (one of it's leads) being on the transistor side rather than the rail side has of little to no difference at all in it's performance.

Cheers

Then why did Nelson change the circuit?

Quote:

Originally Posted by JojoD818

P3 can be added "off-board", but I was under the impression that one needs a distortion analyzer to perfectly adjust this. It wouldn't make any sense adjusting this by ear and everyone has this tool so maybe it makes more sense to leave P3 at the moment.

I believe it is so to take into account the voltage drop in the resistor.

I did say it has little to no difference at all because imho it is a minor "change the circuit" thing but I now realize this may mean the world to others and so it (the board) can still be configured to follow suit.

Quote:

So why even build the circuit then?

P3 was, as I understood it, added to completely minimize the effects of non-match jfets that may lead to distortion. Without P3, the amplifier still behaves and performs as published. It is therefore left to the builder if he/she will build it with or without P3.

Part of getting the best sound out F5 and other amplfiers is tweaking for different amounts of harmonic content which make up it's characteristic sound. It's the small things that make a difference in the character. Otherwise we'd be better off building a chip amp. Solder one chip on a board and be done with it.

So to say it makes no difference, seems like you are not impartial because the boards you have here don't have those changes.

Part of getting the best sound out F5 and other amplfiers is tweaking for different amounts of harmonic content which make up it's characteristic sound. It's the small things that make a difference in the character. Otherwise we'd be better off building a chip amp. Solder one chip on a board and be done with it.

So to say it makes no difference, seems like you are not impartial because the boards you have here don't have those changes.

I meant the thermistor, not the P3. And like I said, P3 can still be employed easily by just bending the leads of the trimmer and soldering it on top of the board.

Hi,
I hope the diyaudio store is not waiting to see how the Mayan thing unfolds before deciding to release the F5T V3 boards...
Do we have a tentative date on when these will be available in the store?